I. Field of the Invention
This invention relates to cutting tools and particularly to rotatable cutting tools of the type having at least one cutting element the position of which relative to the tool is adjustable by remotely controllable adjusting devices. More particularly, this invention relates to improved actuators for remotely controlled adjusting of relative position of cutting elements of rotatable cutting tools.
II. Description of Related Art
Known rotatable tools comprising position adjustable cutting elements use various means for effecting changes of position of the cutting elements. Examples of such rotatable tools using mechanical actuating devices are illustrated in EP Patent Application No. 1123766. An example of a rotatable tool using hydraulic actuating devices requiring supply of hydraulic fluid is illustrated in Japanese Utility Model Application No. 62-201231. Tools of this type have the inherent disadvantage of requiring couplings for supply of hydraulic fluid through the tool driving device. U.S. Pat. No. 4,941,782 illustrates tools of the type wherein pneumatic pressure is supplied to a rotatable tool from an external source to control operation of a hydraulically operated device within the tool body. Such known tools have the disadvantage of requiring sliding seals between internal pistons and cavities containing hydraulic fluids. Such seals, if not routinely replaced and reconditioned are a common source of leakage of hydraulic fluid, impairing operation of the adjusting devices. In light of known rotatable tools providing remotely controllable hydraulically operated adjusting devices for adjusting the position of cutting elements, there is a need for improved actuators for such tools to overcome the disadvantages associated with the known hydraulic devices.